The date displayed in the repository commits is in fact the Author Date and not the Commit Date from the commit. The difference can be found here, but it's summarised by:

You may be wondering what the difference is between author and committer. The author is the person who originally wrote the work, whereas the committer is the person who last applied the work. So, if you send in a patch to a project and one of the core members applies the patch, both of you get credit – you as the author, and the core member as the committer.

This makes it confusing for some customers who know the difference between the two dates. Also, Bitbucket Cloud displays the same date but calls the column "Date" which avoids confusion.